This may be able to be resolved under the "Staingate" repair program. "Staingate" is where the internal monitor of Retina MacBooks has the anti-reflective coating peeling or degrading. If you have a Macbook model that is listed under the repair program (see link), then Apple will fix this at no charge.
If the Apple store gives you issues, contact Apple Customer service and kindly explain the situation. Sometimes a softer approach goes a long way to helping you get the issue resolved (coming from a former retail manager). Just let them know you are aware of the below repair program, which will extend your warranty for 4 years from your original purchase date.
Apple Retina Screen "Staingate" repair program link:
apple-extends-free-staingate-repairs